Salt scaling dynamics in microfluidic channels: Impact of channel geometry and process parameters

Abstract

Salt scaling, a prevalent challenge in industrial processes, often leads to reduced efficiency, equipment failure, and environmental impact. Understanding and mitigating scaling in miniaturized systems for process intensification applications is crucial. In this study, we indigenously developed and utilized microfluidic reactors to investigate calcium carbonate (CaCO₃) scaling dynamics in microfluidic channels, offering real-time visualization under continuous flow; a significant advancement over static methods. We explore the impact of channel geometry (curvature of 0°, 45°, 90°, and 135°) and process parameters (temperature, supersaturation index (SI), and flow velocity) on CaCO₃ deposition behavior. Our findings reveal significant influences: higher temperature and SI promote deposition, while microchannel curvature and increased flow velocity enhance removal. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses confirmed the morphology and phase changes of the deposited CaCO₃. Calcite and aragonite were the dominant polymorphs, with their occurrence influenced by temperature and SI. These insights can be translated to the design and operation of miniaturized equipment for process intensification, such as micro heat exchangers. By understanding and controlling scaling phenomena, this research might pave the way for improved performance, sustainability, and resource efficiency in various industrial settings.